Timed protocol verification for Estelle-specified protocols

Abstract

This paper presents a new model, which is named Timed Communicating State Machine (TCSM), for specifying protocols that incorporate timed properties as part of their specifications. The TCSM model is similar to the Extended Communicating Finite State Machine (ECFSM) model. The major extension is providing an additional mechanism, i.e., a time interval attribute, for describing the timed properties. We also propose the corresponding formal TCSM-based timed verification scheme, i.e., a new timed global state reachability analysis. In the new timed global state reachability analysis, the exploration is decided by the predicate, the time relationships, and/or the input event. Using the TCSM model and the timed verification scheme, an Estelle-based Timed Protocol Verification System (ETPVS) has been developed on SUN SPARC workstations. In this way, timed protocols can be formally specified in Estelle and can also be verified using ETPVS.

Using Change Impact Analysis to Select Tests for Extended Finite State Machines

“…Unlike these tests descriptions of tests λ 4 and λ 5 do not contain all the information about the transitions appearing in their test runs. Determining if these tests are affected needs additional effort in terms of analyzing nonexplicit transitions.…”

“…Several applications can be modeled using EFSMs that contain only explicit transitions [7], [5]. All the tests are fully-observable for such EFSMs and tests affected by a given change can be automatically selected for regression testing as described above.…”

“…Applications dealing with temporal aspects such as delays and timers are more naturally expressed using EFSMs having non-explicit transitions [5]. For instance, the bank web service described in Section 1 includes a timer synchronized with deposits and withdrawals and a delay counter to accrue and transfer bonus into each bank account.…”

“…EFSMs have been extensively used to model software programs [6], [7] communication systems, and protocols [5]. Transition-based models such as Control-flow automata, and Symbolic Abstraction Language (SAL), similar to EFSMs, are used by existing software verification tools.…”

“…Note that the transition t 12 has been removed 5. Interaction among transitions is analyzed using post-images and preimages computed from the transitions.…”